Military vehicles/crafts are subjected to threats, e.g. in a situation of war, wherein they constitute targets for attacks from land, air and sea. It is therefore desired that the vehicle is as difficult as possible to detect, classify and identify. For this purpose military vehicles are often camouflaged with regard to the background so that they become difficult to detect, classify and identify by means of using the bare eye. Furthermore, they are difficult to detect in darkness with different types of image intensifiers. A problem is that attacking crafts such as combat vehicles and aircrafts are often equipped with a combination of one or more active and/or passive sensor systems comprising radar and electro-optical/infrared (EO/IR) sensors whereby the vehicles/crafts becomes relatively easy targets to detect, classify and identify. Users of such sensor systems search for a particular type of thermal/reflecting contour which is not normally occurring in nature, usually different edge geometries, and/or large evenly heated surfaces and/or evenly reflecting surfaces.
In order to provide protection against such system different types of technologies within the field of signature adaptation are used today. Signature adaptation technologies comprises constructional actions and are often combined with advanced materials technology in order to provide a specific emitting and/or reflecting surface of the vehicles/crafts in all wave length areas wherein such sensor system operate.
U.S. Pat. No. 7,215,275 B2 describes an apparatus for adaptive camouflage with independent control of both temperature and apparent color. The apparatus has cells or individual pixels behind a transparent outer layer. The temperature of the outer layer is controlled by a heat transfer fluid flowing in a closed circuit in each cell, the fluid being cooled or heated by Pelletier elements located behind the assembly. Color changes can be activated separately at the back of the transparent layer by the rotation of metallic triangles whose sides are covered with various color paints, the triangles being located behind the transparent layer. The apparent signature of the assembly can then be varied by adapting the signature of the various cells to current environmental conditions when background conditions alter. This solution has the drawback of that it provides a slow response time for adapting the thermal signature. Furthermore it is difficult to a good resolution of the thermally adapting structure without the use of excessive amount of pipes for transporting the fluid.
WO/2010/093323 A1 describe a device for thermal adaptation, comprising at least one surface element arranged to assume a determined thermal distribution, said surface element comprising a first heat conducting layer, a second heat conducting layer, said first and second heat conducting layers being mutually thermally isolated by means of an intermediate insulation layer, wherein at least one thermoelectric element is arranged to generate a predetermined temperature gradient to a portion of said first layer. The invention also relates to an object such as a craft. This solution only enables thermal signature adaptation and is not suitable for implementation in objects such as vehicles/crafts, which of constructional reasons do not enable storage of excess heat provided from said at least one thermoelectric element.